This invention relates to sanitary napkins, and particularly to an improved, easily-manufactured, adhesively secured napkin with integral moisture barriers.
Sanitary napkins incorporating moisture barriers and adhesive strips to releasably secure them to garments are very well known, several being described in my U.S. Pat. No. 3,888,254, issued June 10, 1975. Some of the prior art napkins employ a single longitudinal adhesive strip extending substantially the entire length of the pad and other types employ adhesive attachments at each tab end. The tab end attachment type tends to be superior over the single longitudinal adhesive strip in that it reduces the tendency of the outer layer, or garment side of the pad, to separate from the filler, thereby permitting the moisture barriers to shift or incline from their original position to lower the effectiveness of the moisture barriers.
While some sanitary napkin designs employ lateral adhesive strips at each tab end, they still suffer a serious defect in that the lateral adhesive strips adhere only to the surface layer of the cover fabric. Therefore, the remaining layers are free to curl or double over during use. These prior art defects are overcome by the present invention.
Briefly described, the sanitary napkin of the present invention comprises an absorbent filler pad wrapped with absorbent fabric layers and moisture barriers, and having lateral adhesive strips on each tab. The pervious material and the moisture barrier layers are integrally formed by the simple process of heat-pressure bonding, while the layers that extend beyond the ends of the filler pad are more rigidly bonded while simultaneously crimped to form tab ends that do not separate or curl over during use. The napkin pad itself is formed of a rectangular non-woven fabric sheet, two-thirds of which is covered with a sheet of moisture barrier. The highly absorbent filler pad is shorter than the fabric sheet and is inserted on the center third of the fabric sheet and between that sheet and the moisture barrier. The fabric third that is uncovered by the moisture barrier is folded over the top of the center third and is in direct contact with the moisture barrier. The opposite third having the moisture barrier is folded over the top of the center third. These alternating layers extend beyond the ends of the filler pad. Heat and pressure is applied to bond the layers together, with higher pressure being applied to the tab ends to securely bond and crimp together the tab ends. An adhesive strip with a peel-off protecting strip may then be applied to the tab ends.
The advantages of the sanitary napkin of the invention are that the fused and crimped adhesive tab ends prevent separation of the layers so that the napkin remains completely intact without curling or doubling over during use. In addition, the pad adjusts very readily to body activity and permits a lengthwise "pull" or stress on the entire pad rather than just on the fabric layer that is attached to the undergarment. Furthermore, the napkin is not bulky or bunchy since its positioning during use is determined by the end-to-end attachment which allows for a certain amount of undergarment "give" without interference with its comfortable and indiscernible attachment.
Another important advantage is that the napkin comprises a comparatively simple manufacturing design that may be easily produced in various desired sizes.